Bottom slitter band



y 1, 1966 G. w. KARR 3,253,494

BOTTOM SLITTER BAND Filed Feb. 5, 1964 INVENTOR. Gena la Wffa'rr /ATTORN United States Patent 3,253,494 BOTTOM SLITTER BAND Gerald W. Karr, West Chester, Pa., assignor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Feb. 3, 1964, Ser. No. 342,092 6 Claims. (Cl. 83665) The present invention relates to improvements in web slitting mechanisms and particularly to a slitter band having an improved arrangement for making the band and for mounting it on a supporting shaft.

In a slitting mechanism particularly of the type used in a machine for slitting a traveling paper web, upper circular slitter knives coact with lower slitter bands to slit a wide web into a plurality of widths. The bands are mounted on a supporting rotary shaft and are manufactured independently of the shaft for mounting on the shaft for assembly. Where a plurality of slitters are provided a number of bands are mounted on a shaft and are adjustable thereon to be positioned in accordance with the width of strips to be cut from a traveling web. In a high speed paper machine wherein the web will travel on the order of 6000 feet per minute it is essential that the band be dynamically balanced to prevent vibration to insure a clean smooth cutting of the web. When the slitter bands must be quite narrow for cutting narrow strips from'a web it is difiicult to obtain a mounting arrangement which is easy to machine and which is accurate so that the narrow bands which have relatively narrow supporting surfaces will be accurately mounted and so that their side cutting edges will lie in a plane accurately normal to the axis of the supporting shaft. A conventional way of making a slitter band has been to bore a hole through a cast band at the center of the band, and then bore or machine away an off center portion of the hole which covers an arc of at least 180 with the portion cut away being drawn away from the shaft by a band locking arrangement such as a set screw which draws the finished surface of the band against a supporting shaft. This arrangement encountered a number of difficulties in that a narrow band provides a supporting cylindrical surface of relatively narrow width, and inaccuracyin the location or direction of the axis of the first bored hole will result in the band not being mounted true on the shaft and chattering with respect to its cutter knife and improper cutting and rapid wear of the parts.

It is accordingly an object of the present invention to provide a cutter band of improved structure wherein the structure can particularly be used on narrow bands and yet result in reliable true mounting of the band on a shaft.

A- still further object of the invention is to provide an improved cutter band structure wherein a plurality of bands can be mounted on a shaft in relatively close stacked relationship without interference from adjacent supporting surfaces.

A still further object of the invention is to provide an improved cutter band structure with supporting surfaces for engaging a supporting shaft wherein the surfaces are more easily constructed and machined than with arrangements heretofore available. v

Other objects, 1 advantages and features will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiment thereof in the specification, claims and drawings in which:

FIGURE 1 is a somewhat schematic elevational view showing a plurality of slitter bands and knives constructed and operating in accordance with the principles of the present invention and arranged so that the bands can be moved relatively close together, with FIGURE 1A showing the positions of the bands moved together;

FIGURE 2 is a side elevational view of a band constructed in accordance with the principles of the present invention;

FIGURE 3 is a fragmentary sectional view taken substantially along line IIIIII of FIGURE 2;

FIGURE 4 is a fragmentary sectional view taken substantially along line IV-IV of FIGURE 2;

FIGURE 5 is a fragmentary sectional view taken sub- I stantially along line VV of FIGURE 3; and

FIGURE 6 is a fragmentary sectional view taken substantially along line VIVI of FIGURE 4.

As shown on the drawings:

FIGURE 1 shows a portion of aslitter assembly having a plurality of upper circular knives 10 and 11 with edges that coact with the edges of lower slitter bands 12 and 13. The slitter bands may be driven if desired as may be the knives, or only one of the bands or knives may be driven at a predetermined optimum speed relative to the travel of the web which passes through the cutting nip formed between the knives and bands. The axial spacing between the cutting nips determines the width of strip cut from the overall web. The settings of the unit may be changed 'to change the width of strips cut and in certain instances of cutting a very narrow strip the bands will necessarily have to be moved very close together.

'The bands are mounted on a support shaft 14 having a cylindrical outer surface.

As illustrated in FIGURE 2 the bands are annular in shape and may be cast and subsequently machined, and the bands have a cylindrical outer surface and at least one side cutting edge, and normally both sides will have cutting edges 15 and 16.

The bands are finished by hardening the side and outer surfaces such as by flame hardening and in some circumstances the surfaces may be coated with a hard material. As above stated, the present structure avoids the steps heretofore necessary in machining the inner supporting surfaces of the bands. Heretofore approximately {/2 or less of the inner circumferential surface was finished to an arc concentric with the center of gravity of the finished band and the rest of the inner surface was machined slightly off center so that a locking arrangement such as a set screw would pull the finished supporting surface of the band tightly against the shaft. This arrangement is however impractical with a very narrow band and increases machining requirements with the lighter bands.

In the present arrangement side lugs or supporting elements 17 and 18 are provided with a first pair 17 axially separated and projecting axially outwardly from the sides of the band. The supporting elements 18 also extend laterally outwardly from the sides of the band and the pairs 17 and 18 are spaced apart a distance less than so \as to radially and supportingly engage a supporting shaft when a locking set screw 21 is tightened. The set screw 21 is preferably located diametrically opposite a location intermediate the supporting elements 17 and 18.

At the axially outer edges of the supporting feet or supporting elements 17 and 18 are concave radially inwardly facing arcuate supporting surfaces 19 and 20. Thes supporting surfaces are spaced axially outwardly a distance greater than any other part of the band. They are positioned axially outwardly a distance greater than balancing lugs 23 which are positioned at the location of the set screw to dynamically balance the band and compensate for the weight of the supporting elements 17 and 18.

The relative axial projection of the lugs 23 and the feet 17 (lugs 18 extend outwardly about the same distance as lugs 17 and further than lugs 23) may be osberved by comparing FIGURES 5 and 6. It will thus be seen that the inner concave supporting surfaces 19 and 20 may be readily machined by positioning the band on a rotating o arbor without the lugs 23 striking or interfering with the cutter for each rotation of the band. In other words the surfaces 19 and 20 can be accurately machined by mounting the band on a rotating cutter and the machining accomplished a distance axially spaced from the location of any other part of the band, and particularly the balancing lug 23.

The surfaces 19 and 20 are finished so that they have a concave curvature substantially the same radius as the supporting shaft, and they are finished with their radial center coinciding with the dynamically balanced radial center of the band. Thus as the shaft rotates about its axis, the band mounted thereon will rotate about its dynamically balanced radial center.

In operation the bands 12 are formed with the pairs of supporting elements 17 and 18 projecting axially therefrom, and the bands are mounted on a finishing machine with the inner surfaces 19 and 20 of the lugs being finished. The bands are then mounted on a supporting shaft such as 14, FIGURE 1, and the locking set screws 21 tightened. The pairs of surfaces 19 and 20 are separated sufficiently axially so that the cutting edges 15 and 16 of the band will be positive and true with the axial center of the shaft. In other words the cutting edges will lie in an accurate plane at right angles to the shaft axis. When the bands are to be moved close together they are rotated slightly so that their lugs can be in stacked relationship. For example, the lugs 17 can be moved against the side of an adjacent band 13, and its supporting elements or lugs 18 can be moved against the side of the band 12. The adjacent band and other bands may be placed on the shaft sequentially with the bands in the same position or tipped over as shown for the band 13 which has lugs 18' and 23. The supporting elements for each band thus still provide axially spaced supports without reducing the closeness to which the bands can be located.

Thus I have provided a cutter band structure which avoids disadvantages of structures heretofore available and provides a band which is inexpensive to manufacture, obtains accurate support and improved cutting operation at high cutting speeds, is lightweight and achieves other advantage as above set forth.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. A slitter band structure for mounting on a cylindrical shaft comprising,

an annular slitter band having a cylindrical outer surface with at least one side cutting edge,

first and second pairs of supporting elements projecting axially from the sides of the band and spaced apart a distance less than 180,

balancing lugs on the sides of the band opposite the elements projecting axially from the band a distance less than said elements,

radially inwardly facing surfaces on the elements having arcuate machined surfaces with a center coinciding with the dynamically balanced center of the band and being axially outwardly a greatly distance than the lugs to be machined without interference with the lugs,

and a locking means opposed to said supporting elements for radially engaging a shaft and drawing said surfaces against the shaft.

2. A slitter band structure for mounting on a cylindrical shaft comprising,

an annular slitter band having a cylindrical outer surface with at least one side cutting edge, first and second pairs of supporting elements projecting axially from each side of the band spaced apart less than said elements having arcuate inner surfaces finished to substantially the same radius as a supporting shaft and positioned so that the dynamic center of the ring is at the radial center of the surfaces, and a locking means opposed to said surfaces for radially engaging the shaft and drawing the surfaces against the shaft. 3. A slitter band structure for mounting on a cylindrical shaft comprising,

an annular slitter band having a cylindrical outer surface with at least one side cutting edge, first and second pairs of supporting lements projecting axially from each side of the band spaced apart less than 180 with radially inwardly facing shaft engaging surfaces, balancing lugs on the sides of the band opposite said supporting elements for dynamically balancing the band, and a locking means opposed to said supporting elements for radially engaging a shaft and drawing said supporting elements against the shaft. 4. A slitter band structure for mounting on a cylindrical shaft comprising,

an annular slitter band having a cylindrical outer surface with at least one side cutting edge, first and second pairs of supporting elements projecting axially from each side of the band spaced apart less than 180 with radially inwardly facing shaft engaging surfaces, and a radially inwardly extending set screw for engagement with a supporting shaft to draw said elements against the shaft. 5. A slitter band structure for mounting on a cylindrical shaft comprising,

an annular slitter band having a cylindrical outer surface with at least one side cutting edge, first and second pairs of supporting elements projecting axially from the sides of the band spaced apart a distance less than 180 and having radially inwardly facing surfaces for engaging a shaft so that the dynamic center of the band will coincide with the rotational center of the shaft, balancing lugs on the sides of the band opposite the elements projecting axially from the band a distance less than said elements, and a locking means opposed to said supporting elements for radially engaging a shaft and drawing the elements against the shaft. 6. A slitter band structure for mounting on a cylindrical shaft comprising,

an annular slitter band having a cylindrical outer surface with at least one side cutting edge, first and second pairs of supporting elements projectingaxially from each side of the band spaced apart less than 180 with radially inwardly facing shaft engaging surfaces, and a locking means opposed to said supporting elements for radially engaging a shaft and drawing said supporting elements against the shaft.

References Cited by the Examiner UNITED STATES PATENTS ANDREW R. J UHASZ, Primary Examiner. 

1. A SLITTER BAND STRUCTURE FOR MOUNTIG ON A CYLINDRICAL SHAFT COMPRISING, AN ANNULAR SLITTER BAND HAVING A CYLINDRICAL OUTER SURFACE WITH AT LEAST ONE SIDE CUTTING EDGE, FIRST AND SECOND PAIRS OF SUPPORTING ELEMENTS PROJECTING AXIALLY FROM THE SIDES OF THE BAND AND SPACED APART A DISTANCE LESS THAN 180*, BALANCING LUGS ON THE SIDES OF THE BAND OPPOSITE THE ELEMENTS PROJECTING AXIALLY FROM THE BAND A DISTANCE LESS THAN SAID ELEMENTS, RADIALLY INWARDLY FACING SURFACES ON THE ELEMENTS HAVING ARCUATE MACHINED SURFACES WITH A CENTER COINCIDING WITH THE DYNAMICALLY BALANCED CENTER OF THE BAND AND BEING AXIALLY OUTWARDLY A GREATLY DISTANCE THAN THE LUGS TO BE MACHINED WITHOUT INTERFERENCE WITH THE LUGS, AND A LOCKING MEANS OPPOSED TO SAID SUPPORTING ELEMENTS FOR RADIALLY ENGAGING A SHAFT AND DRAWING SAID SURFACES AGAINST THE SHAFT. 